Transfer device for cryogenic fluids

ABSTRACT

Disclosed is a device for transferring a cryogenic fluid from its storage vessel to cryostat or other vessel. The device is an open ended tube of sufficient length to permit its lower extremity to project below the surface of the fluid when it is inserted into an opening in the vessel. The tube is fitted with a collar which forms a substantially airtight seal between the tube and the opening. A heater capable of producing sufficient heat to vaporize part of the fluid is attached to the tube. The vaporization creates an internal pressure which forces the fluid up through the tube. By insulating the heater from the tube so that the fluid forced into the tube is not vaporized, a steady flow of cryogenic fluid is delivered to a desired location, e.g., a cryostat.

[ Mar. 7, 1972 [54] TRANSFER DEVICE FOR CRYOGENIC FLUIDS [72] Inventors: Chin Huan Cheng, Midland; Donald E.

Leonard, Shepherd, both of Mich.

[731 Assignee: The Dow Chemical Company, Midland,

- Mich.

221 Filed: Feb. 5, 1970 211 App1. No.: 9,004

[58] FieldofSearch ..219/271,272, 275,307,319; 62/50, 51, 55; 137/341; 222/146; 261/142; 417/52 [56] References Cited UNITED STATES PATENTS 3,092,974 6/1963 Haumann et al ..62/50 X Primary Examiner.l. V. Truhe Assistant Examiner-C. L. Albritton Attorney-Griswold 8L Burdick, Jerome l... Jeffers and William R. Norris [5 7] ABSTRACT Disclosed is a device for transferring a cryogenic fluid from its storage vessel to cryostat or other vessel. The device is an open ended tube of sufficient length to permit its lower extremity to project below the surface of the fluid when it is inserted into an opening in the vessel. The tube is fitted with a collar which forms a substantially airtight seal between the tube and the opening. A heater capable of producing sufficient heat to vaporize part of the fluid is attached to the tube. The vaporization creates an internal pressure which forces the fluid up through the tube. By insulating the heater from the tube so that the fluid forced into the tube is not vaporized, a

steady flow of cryogenic fluid is delivered to a desired location, e.g., a cryostat.

4 Claims, 1 Drawing Figure Discharge Patented March 7, 1972 3,648,018

INVENTORS. Chin Huan Che/7g BY Dona/d E. Leona/'0 Arron/v5) TRANSFER DEVICE FOR CRYOGENIC FLUIDS Certain chemical reactions and physical measurements must be run at extremely low temperatures. For example, those chemical reactions which are'highly exothermic must be kept cold to prevent explosions or decomposition of the reactants due to evolution of large amounts of heat energy. The use of dry ice (m.p.-78.5 C.) will not provide sufficient cooling in some instances. Liquified gases, also known as cryogenic fluids, are used in these cases because of their low temperatures. For example, liquid nitrogen (b.p.l95.8 C.), liquid helium (b.p.--268.6 C.) and liquid oxygen (b.p.- 183.0 C.) are useful cryogenic fluids. Liquid nitrogen is espe cially useful in laboratory operations due to its low cost.

These cryogenic fluids are stored in heavily insulated containers to prevent their rapid evaporation, and there is a problem in transferring them from their storage vessels to the area it is desired to cool. The general practice of transferring a cryogenic fluid from its storage vessel is by pressurizing the vessel with gas to force the liquid out through a transfer tube into a cryostat. Compressed air at several p.s.i. is generally used to transfer liquid nitrogen. A simpler way to pressurize the vessel is to introduce heat energy into it to evaporate the liquid itself. The advantages of this method are less chance of contamination and greater convenience.

Accordingly, it would be desirable and it is an object of the present invention to provide a novel device for transferring a cryogenic fluid, i.e., liquid, from its storage vessel to a cryostat.

An additional object is to provide such a device which is simple to operate and does not require an external gas supply.

A further object is to provide such a device which requires only small amounts of heat energy in order to effectively transport the fluid.

Another object is to provide such a device which produces a continuous, uniform transfer of cryogenic fluid from its storage vessel to a cryostat.

One embodiment of the invention is illustrated by the FIGURE.

An open ended tube 13 is provided with a collar 14 to snugly fit the opening in the storage vessel. Optionally, the opening in the storage vessel is fitted with a rubber hose 15. The hose allows for a better seal between the collar and the opening but is by no means critical to the operability of the device. The tube is fitted with an electrical resistance heater 16 which is separated from the tube by sufficient insulation 17 to prevent fluid which enters the tube from being vaporized. Vaporization of a substantial amount of fluid in the tube is prevented since it is desired to evenly dispense liquid rather than a liquid gas mixture. The heater is connected to a power source 18.

The figure illustrates the device inserted into a storage vessel for cryogenic fluid in an operable manner. The tube is of sufficient length to protrude below the level of the liquid. Preferably, it extends close to the bottom of the vessel so as to dispense liquid even when the vessel is nearly empty.

In operation the heater is operated so as to vaporize enough of the cryogenic fluid to create an internal pressure sufficient to force fluid up through the tube. vaporization of the fluid in the tube could be prevented by physical separation of the tube and heater; however, insulating the heater from the tube with a coating which does not conduct a substantial amount of heat will prevent vaporization and result in a device which can be handled conveniently. That part of the tube which projects from the storage vessel is normally wrapped with insulation 19 to prevent vaporization of the fluid after leaving the storage vessel. Flow of the fluid can be conveniently stopped by turning off the heater and releasing the pressure such as by opening a vent 20 in the collar. The vent should be of such design that it can cause an airtight seal when closed and be readily opened to relieve internal pressure in the vessel.

We claim:

1. A device for removing a cryogenic liquid from a storage vessel which comprises:

a. an open ended tube of sufficient length to permit its lower extremity to project below the surface of the liquid when it is inserted into an opening in the storage vessel,

b. a collar adapted to the tube to form a substantially airtight seal between the tube and the opening, said tube being airtight in the area defined by the surface of the liquid and the collar, and

c. means for producing sufficient heat energy to vaporize the cryogenic liquid in the storage vessel, said means attached to the tube and sufficiently insulated from it to prevent its heat energy from evaporating liquid inside the tube.

2. The device as described in claim 1 wherein the heating means is an electrical resistance heater.

3. The device as described in claim 1 wherein that part of the tube which projects from the storage vessel is sufficiently insulated to prevent vaporization of the liquid after leaving the vessel.

4. The device as described in claim 1 wherein the collar is equipped with a vent which is capable of being sealed or opened. 

1. A device for removing a cryogenic liquid from a storage vessel which comprises: a. an open ended tube of sufficient length to permit its lower extremity to project below the surface of the liquid when it is inserted into an opening in the storage vessel, b. a collar adapted to the tube to form a substantially airtight seal between the tube and the opening, said tube being airtight in the area defined by the surface of the liquid and the collar, and c. means for producing sufficient heat energy to vaporize the cryogenic liquid in the storage vessel, said means attached to the tube and sufficiently insulated from it to prevent its heat energy from evaporating liquid inside the tube.
 2. The device as described in claim 1 wherein the heating means is an electrical resistance heater.
 3. The device as described in claim 1 wherein that part of the tube which projects from the storage vessel is sufficiently insulated to prevent vaporization of the liquid after leaving the vessel.
 4. The device as described in claim 1 wherein the collar is equipped with a vent which is capable of being sealed or opened. 